Unlockable Modes
Invisible Enemy - Complete Real Survivor
Once Again.. - Complete the Game Once on Any Difficulty
One Dangerous Zombie - Complete the game with Both Chris and Jill on Normal or Higher on the same save file.
Real Survivor - Complete the game on Normal

Costume Unlocks

Code Veronica - Clear the game twice with Chris on any Difficulty
Nemesis Outfit - Clear the game twice on any difficulty as Jill
Sarah Connor - Clear the game once on any difficulty as Jill
The Mexican - Clear the game with Chris on any Difficulty

if you cannot download trainer then go to Chrome/Firefox's settings, specifically to the Privacy settings and simply unchecking the "Enable phishing and malware protection" option.

Some Game Trainers are sometimes reported to be a Virus or Trojan,
the most common is a keylogger called HotKeysHook or the file
has been packed/protected with VMProtect or Themida and
is recognized as Win32/Packed.VMProtect or Win32/Packed.Themida.
In ALL cases this is a FALSE ALARM as NONE
of the Game Trainers @ GCW contain known malicious code! More info in
the PC
Games FAQ!